Filament fastener that cures with composite part

ABSTRACT

Systems and methods for filament fastener that cures with composite part. One embodiment is a method of fabricating a composite part. The method includes placing layers of reinforcement fibers over a tool to form a laminate of composite material to be cured with a first resin, forming a filament fastener comprising bundled fibers with one or more texture elements around the bundled fibers, and coating the filament fastener with a second resin that is chemically compatible with the first resin. The method also includes inserting the filament fastener into the laminate through a plurality of the layers, and curing the filament fastener within the laminate to bind the plurality of the layers of the laminate with the one or more texture elements of the filament fastener via bonding of the first resin and the second resin to form the composite part with delamination resistance.

FIELD

This disclosure relates to the field of manufacturing, and moreparticularly, to manufacturing of composite parts.

BACKGROUND

Composite parts, such as carbon fiber reinforced plastics (CFRP), arewidely used in aerospace and other applications because of theirfavorable strength-to-weight ratio. Composite parts may be fabricated bylaying of plies of prepreg or by resin infusion of dry fibers. Comparedwith traditional metal aircraft parts that are mechanically assembledtogether, these composite fabrication techniques enable manufacturinglarge integrated aircraft structures having complex shapes withincreased strength, reduced weight, and using fewer mechanical fastenersfor assembly.

However, composite parts are susceptible to delamination, where layersof the material or joined components fracture and separate. Therefore,after a composite part is formed it is often fortified with disbondfasteners to prevent delamination. These mechanical fasteners arelabor-intensive to install, may cause stress risers and microcracking inthe composite material, add significant weight to the aircraft, andincrease production build times when factory flow is critical.Accordingly, it is desirable to produce composite structures havingsufficient delamination resistance while also having reduced reliance ontraditional disbond fasteners.

SUMMARY

Embodiments described herein provide a filament fastener that cures witha composite part. The structure of the filament fastener is alightweight thread or post having a diameter sufficiently small so as toseparate fibers of the part instead of cutting the fibers as it isinserted into an uncured part. Additionally, the filament fastener mayinclude texture around it or twisted to create a screw-like filament toenable higher surface area bonding with the composite resin system ofthe part such that its removal involves some type of fracture along thetexture or filament. After hardening inside the composite part duringcure, the filament fastener is integrally formed within the part toprevent cracks and delamination of the part. Compared with traditionaldisbond fasteners, the filament fastener yields fabrication and assemblysavings and provides improved out-of-plane toughness and interlaminarshear strength while reducing the weight of the final part.

One embodiment is a method of fabricating a composite part. The methodincludes placing layers of reinforcement fibers over a tool to form alaminate of composite material to be cured with a first resin, forming afilament fastener comprising bundled fibers with one or more textureelements around the bundled fibers, and coating the filament fastenerwith a second resin that is chemically compatible with the first resin.The method also includes inserting the filament fastener into thelaminate through a plurality of the layers, and curing the filamentfastener within the laminate to bind the plurality of the layers of thelaminate with the one or more texture elements of the filament fastenervia bonding of the first resin and the second resin to form thecomposite part with delamination resistance.

Another embodiment is a composite laminate that includes layers ofreinforcement fibers forming a stack of composite material to be curedwith a first resin, and a filament fastener including bundled fiberswith one or more texture elements around the bundled fibers, and asecond resin chemically compatible with the first resin that saturatesthe filament fastener. The filament fastener is configured to insertinto the stack through a plurality of the layers of reinforcementfibers, and to cure within the stack to bind the layers of the stackwith the one or more texture elements of the filament fastener viabonding of the first resin and the second resin to form the compositelaminate with delamination resistance.

Yet another embodiment is an apparatus that includes a filament fastenercomprising: a core thread comprising bundled fibers, a texture threadwrapped around the core thread in a spiral, and a resin that saturatesthe filament fastener and orients the texture thread with respect to thecore thread to form the filament fastener in a helical shape. Thefilament fastener is configured to insert into a composite laminatethrough one or more layers of reinforcement fibers laid up as a stack ofcomposite material, and to cure within the stack via the resin to bindthe layers with the texture thread of the filament fastener.

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments or may be combined in yetother embodiments, further details of which can be seen with referenceto the following description and drawings.

DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are now described, by way ofexample only, with reference to the accompanying drawings. The samereference number represents the same element or the same type of elementon all drawings.

FIG. 1 shows a composite laminate in an illustrative embodiment.

FIGS. 2A-2C are side views of various types of filament fastenersinserted into a laminate in illustrative embodiments.

FIG. 3 is a flowchart illustrating a method of fabricating a compositepart in an illustrative embodiment.

FIG. 4 shows a filament fastener insertion system in an illustrativeembodiment.

FIG. 5 is a flow diagram of using the filament fastener insertion systemto install a filament fastener in an illustrative embodiment.

FIG. 6 is a side view of a composite part including angled filamentfasteners in an illustrative embodiment.

FIG. 7A is a side view of an uncured laminate enhanced with non-rigidfilament fasteners in an illustrative embodiment.

FIG. 7B is a side view of a cured laminate in an illustrativeembodiment.

FIG. 8A is a side view of an uncured laminate enhanced with rigidfilament fasteners in an illustrative embodiment.

FIG. 8B is a side view of a cured laminate in an illustrativeembodiment.

FIG. 9 illustrates a composite part enhanced with filament fasteners inanother illustrative embodiment.

FIG. 10A is a perspective view a joint fastener that includes an arrayof filament fasteners in an illustrative embodiment.

FIG. 10B is a perspective view of a series of steps of installing thejoint fastener 1000 with a laminate in an illustrative embodiment.

FIG. 10C is a side view of the series of steps of installing the jointfastener with the laminate in an illustrative embodiment.

FIG. 10D is a partial bottom view of the joint fastener in anillustrative embodiment.

FIG. 11 is a flow chart illustrating an aircraft manufacturing andservice method in an illustrative embodiment.

FIG. 12 is a schematic diagram of an aircraft in an illustrativeembodiment.

DETAILED DESCRIPTION

The figures and the following description illustrate specific exemplaryembodiments. It will be appreciated that those skilled in the art willbe able to devise various arrangements that, although not explicitlydescribed or shown herein, embody the principles described herein andare included within the contemplated scope of the claims that followthis description. Furthermore, any examples described herein areintended to aid in understanding the principles of the disclosure, andare to be construed as being without limitation. As a result, thisdisclosure is not limited to the specific embodiments or examplesdescribed below, but by the claims and their equivalents.

FIG. 1 shows a laminate 100 for forming a composite part in anillustrative embodiment. The laminate 100 comprises layers 102 ofreinforcement fibers (also referred to as plies) that are laid-up on atool 110 (also referred to as a molding tool). Generally, each layer 102comprises a fabric made from any desired fibers, such as carbon, glass,aluminum, steel, titanium, etc. The fabric may be unidirectional, woven,braided, non-crimp, etc. For example, fibers within each layer 102 ofthe laminate 100 may be aligned parallel with each other, but differentlayers 102 may exhibit different fiber orientations to increase thestrength of the resulting composite along different dimensions.

The layers 102 are cut to size, stacked one on top of another, andtransferred to the tool 110. Each of these steps may be performedmanually or automatically by fabrication machines. The tool 110 isconfigured to shape the laminate 100 according to the desired shape ofthe final composite part. The tool 110 may include multiple formingsurfaces and/or contoured surfaces to form composite parts havingcomplex shapes. A composite part may comprise one or more compositeelements to form a structure.

The laminate 100 includes a resin, such as a thermoset or thermoplasticresin, that solidifies to harden the laminate 100 into a composite part(e.g., for use in an aircraft). For thermoset resins, curing is aone-way process that permanently hardens the laminate 100 into acomposite part. Thermoplastic resins, on the other hand, may return to aviscous form if re-heated. Thus, the resin may include a polyimide, anepoxy, a thermoplastic resin, or any other resin suitable for makingcomposite parts. In some embodiments, the laminate 100 has beenimpregnated with an uncured resin to form what is referred to as aprepreg. Alternatively, the laminate 100 may include what is referred toas dry fiber or a preform which has not been impregnated with resin butis instead infused with resin prior to curing.

The cure process includes applying heat and/or pressure to the laminate100 to bond the resin permeating the layers 102 and harden the matrixcomposite material into a solid structure. After cure, the compositestructure may be removed from its mold, cut, trimmed, or otherwisefinished as desired to provide the final composite part. Unfortunately,the composite part may be susceptible to delamination where layers ofthe material fracture and separate. Current techniques for preventingdelamination often involve installing disbond fasteners (e.g., bolts)after the composite part is formed. This involves drilling holes in thehardened structure which may potentially weaken the structure.Additionally, as described above, the disbond fasteners arelabor-intensive to install and add significant weight to the part whichmay be undesirable for some applications such as the manufacture ofaircraft parts. Moreover, disbond features on parts may not be fastenersbut additional material may be applied to mitigate any disbond by loadredistribution within a part or laminate or as a restraint. These typesof features typically add weight and flow time.

To address these issues, the laminate 100 is enhanced with filamentfasteners 150 that are embedded in the laminate 100 prior to cure toprevent post-cure delamination. The filament fasteners 150 generallycomprise longitudinal members that are inserted through one or morelayers 102 while the laminate 100 is in an uncured state. For example,if layers 102 are arranged along x-y planes, filament fasteners 150 maytraverse two or more layers 102 in a z-direction. Each filament fastener150 includes bundled fibers 152 forming a longitudinal body or threadmember, and one or more texture elements 154 around the bundled fibers152. The filament fastener 150 may also include a tip 156 to facilitateinsertion of the filament fastener into the laminate 100. The textureelement 154 of the filament fastener 150 provides increased surface areathat promotes bonding of the filament fastener 150 with the compositematrix material inside the laminate 100. The bonded surface area of thetexture element 154 advantageously provides friction along an axis ofthe filament fastener 150 after it is hardened within the laminate 100,thereby preventing delamination after the laminate 100 is cured.

FIGS. 2A-2C are side views of various types of filament fasteners201-203 inserted into the laminate 100 in illustrative embodiments. Inthe embodiment shown in FIG. 2A, the filament fastener 201 includes anon-rigid core thread 250 of bundled fibers with fuzzy texture 252around the non-rigid core thread 250. The fuzzy texture 252 may includefibrous material forming soft barbs or feathers that provide surface forbonding along a length of the filament fastener 201. The fuzzy texture252 may be formed via abrasion of outer fibers of the filament fastener201 or may be spun in. Alternatively or additionally, the fuzzy texture252 may comprise chopped fibers extending radially from the non-rigidcore thread 250.

In the embodiment shown in FIG. 2B, the filament fastener 202 includes anon-rigid core thread 260 of bundled fibers with ring texture 262 aroundthe non-rigid core thread 260. The ring texture 262 may comprise annularrings molded to the non-rigid core thread 250 and arranged along alength of the filament fastener 202 to provide surface area (e.g., inthe x-y plane) for bonding. Alternatively, the ring texture 262 maycomprise a spiral that forms a helical shape around the non-rigid corethread 250 similar to screw threads to provide bonding surface area. Thering texture 262 may be oriented on the non-rigid core thread 260 via aresin. Filament fasteners 201-202 may be spooled as a continuous threadthat is inserted into the laminate 100 and cut or that is stitched intothe laminate 100.

In the embodiment shown in FIG. 2C, the filament fastener 203 includes arigid core thread 270 of bundled fibers with spiral texture 272 aroundthe rigid core thread 270. The rigid core thread 270 may comprise acomposite/plastic pin or a metal pin that forms a central spike. Thespiral texture 272 may form a helical shape around the rigid core thread270 similar to screw threads to provide bonding surface area. The spiraltexture 272 may be molded to the rigid core thread 270 via a resin. Thatis, the resin may maintain an orientation of various types of texturewith respect to the filament fastener. Alternatively or additionally,the core of the filament fastener 201-203 may be formed directly into ahelical shape. Thus, the filament fastener 203 may comprise a straightand/or helical shaped javelin to be inserted into the laminate 100. Thefilament fastener 203 may thus comprise a bundle of fibers and resinconfigured as a screw such that no fibers or minimal fibers are brokenin its construction. This may be accomplished by twisting a threadedmandrel around an extruded rod of fiber and resin at a temperature whereforming may take place. For embodiments in which the resin is not thesame as the base laminate, the filament fastener may include athermoplastic that is miscible when cured such that toughness isimparted in the area of insertion. In some embodiments, the rigid coremay be removed such that only the helical element remains in thelaminate(s).

Generally, filament fasteners 201-203 may each include a diameter thatis sufficiently small so as to separate fibers of the laminate 100instead of cutting the fibers as they are inserted. In one embodiment,the diameter of a filament fastener is less than 0.063 inches. In someembodiments, the filament fastener and the laminate comprise a commoncomposite material, and a co-curing process integrally embeds thefilament fastener in the laminate to form a monolithic compositestructure. Additionally, in some embodiments, filament fasteners 201-203may be spun around themselves to form texture structure. In furtherembodiments, the filament fasteners 201-203 included continuous fibersor fibers with an aspect ratio to transfer load along the length of thefilament to cause fracture at some point. For embodiments for which thefilament fastener is rigid or semi-rigid, the filament fastener may beconfigured to withstand insertion into an uncured laminate itself orwith the aid of piercing or tapping tool which does not fracture thebase laminate. Additionally, rigid or semi-rigid filament fasteners maybe spooled or segmented prior to insertion as desired. For filamentfasteners having screw or helical type texture, the pitch of thefilament fastener may match the thickness of the laminate such that wheninserted it imparts minimal out of plane ply distortion. Insertiontechniques for various types of filament fasteners are described ingreater detail below.

FIG. 3 is a flowchart illustrating a method 300 of fabricating acomposite part in an illustrative embodiment. The steps of method 300will be described with respect to the laminate 100 and filamentfasteners 150 of FIG. 1, although one skilled in the art will understandthat the methods described herein may be performed with alternativelaminates and filament fasteners. The steps of the methods describedherein are not all inclusive and may include other steps not shown. Thesteps for the flow charts shown herein may also be performed in analternative order.

In step 302, layers 102 of reinforcement fibers are placed over the tool110 to form the laminate 100 of composite material to be cured with afirst resin. In step 304, a filament fastener 150 is formed comprisingbundled fibers 152 with one or more texture elements 154 around thebundled fibers 152. In step 306, the filament fastener 150 is coatedwith a second resin that is chemically compatible with the first resin.The resins are considered chemically compatible if crosslinking occursduring cure. Alternatively or additionally, the filament fastener 150may be coated with the same resin or a common resin material to be usedto cure the laminate 100.

In step 308, the filament fastener 150 is inserted into the laminate 100through a plurality of the layers 102. In step 310, the filamentfastener 150 is cured within the laminate 100 to bind the plurality ofthe layers 102 of the laminate 100 with the one or more texture elements154 of the filament fastener 150 via bonding of the first resin and thesecond resin to form the composite part with delamination resistance.Method 300 provides a benefit over prior techniques by providingdelamination resistance and/or crack arrestment to the composite partwithout the use of traditional disbond fasteners.

FIG. 4 shows a filament fastener insertion system 400 in an illustrativeembodiment. The filament fastener insertion system 400 is configured toinstall a soft or non-rigid filament fastener 450 into an uncuredlaminate 401. The filament fastener insertion system 400 includes apressure foot 410, a piercing pin 412, a feed pin 414, and a cuttingblade 416. The pressure foot 410 includes a feed channel 420, a filamentinlet 422, and a blade inlet 424. Details of operation of the filamentfastener insertion system 400 are described in greater detail below.

FIG. 5 is a flow diagram 500 of using the filament fastener insertionsystem 400 to install a filament fastener 450 in an illustrativeembodiment. In step 502, the uncured laminate 401 is indexed with thepressure foot 410. The location, depth, and/or angle for installing thefilament fastener 450 in the uncured laminate 401 may be determined by astructure analysis of the part including part thickness, resin flowcharacteristics, and/or material systems. Additionally, the pitch andpattern of installing multiple filament fasteners 450 may vary accordingto such design space elements.

In step 504, the piercing pin 412 is guided through the pressure foot410 (e.g., in the feed channel 420) to pierce the uncured laminate 401and form a hole. The piercing pin 412 may be twisted as it pierces theuncured laminate 401, and held in position for a period of time to allowthe uncured laminate 401 to relax and expand from the piercing pin 412.Additionally, the piercing pin 412 may have a diameter sufficientlysmall so as to pierce the uncured laminate 401 without fracturing itsfibers.

In step 506, the piercing pin 412 is retracted from the uncured laminate401 and slid out of the pressure foot 410. In step 508, the filamentfastener 450 is fed through the pressure foot 410 and into the holeusing the feed pin 414. The filament fastener 450 enters the filamentinlet 422 of the pressure foot 410 and is guided through the feedchannel 420 by sliding the feed pin 414 through the feed channel 420toward the hole. The feed pin 414 may include a barbed nose to grab andfeed the filament fastener 450. In some embodiments, the piercing pin412 enters the uncured laminate 401 with a twist and includes screw-likethreads pitched at an angle such that individual plies or layers are notdistorted out of plane. The filament fastener 450 may include a similaror corresponding twisted pitch and may be inserted as a screw such thatplies/layers are not distorted out of plane and the filament fastener450 is in direct contact with the uncured laminate 401.

In step 510, the filament fastener 450 is cut with the cutting blade416. That is, after the filament fastener 450 is pushed by the feed pin414 to fill the hole, the cutting blade 416 may be inserted through theblade inlet 424 of the pressure foot 410 to cut the filament fastener450 proximate to a top surface of the uncured laminate 401. In step 512,installation of the filament fastener 450 is verified. The cutting blade416 and the feed pin 414 may be retracted from the pressure foot 410,and the pressure foot 410 may be indexed to another position to repeatthe steps and insert another section of spooled fiber filament material.Accordingly, soft or non-rigid fiber filaments may be embedded into anuncured laminate to prevent delamination.

FIG. 6 is a side view of a composite part 600 including angled filamentfasteners in an illustrative embodiment. As shown in FIG. 6, a formedangle between two filament fasteners 650 creates a lock for plies at anapex where the two filament fasteners 650 cross. Additionally, thefilament fasteners 650 may embed at various depths of the composite part600 according to design. For example, a pair of filament fasteners 650may integrate through a total thickness of the composite part 600 andform a first apex 601 outside the composite part 600 or a second apex602 inside the composite part 600. Alternatively or additionally, a pairof filament fasteners 650 may integrate through a middle thickness ofthe composite part and form a third apex 603 inside the composite part600 near its bottom surface, form a fourth apex 604 at or nearmid-thickness, and/or form a fifth apex 605 at a position betweenmid-thickness and the surface. The filament fasteners 650 may embed inthe composite part at any angle including perpendicular or nearlyhorizontal.

FIG. 7A is a side view of an uncured laminate 700 enhanced withnon-rigid filament fasteners 750 in an illustrative embodiment. FIG. 7Bis a side view of a cured laminate 710 in an illustrative embodiment. Asshown in FIG. 7A, the non-rigid filament fasteners 750 may be sewn 701with bobbin or chain stitch, pierced through and cut 702, or cutinternally 703. The process may include other steps that are performedto prepare for curing of the uncured laminate 700. For example, if thelaminate is “dry”, then a resin may be infused or impregnated in thelaminate, such as with Resin Transfer Molding (RTM), Vacuum-AssistedResin Transfer Molding (VARTM), etc. The molding tool and layup may alsobe moved to a curing device at another station. As shown in FIG. 7B,after co-curing with the laminate, the filament fasteners 750 conform tothe forming surfaces of the cured laminate 710.

FIG. 8A is a side view of an uncured laminate 800 enhanced with rigidfilament fasteners 850 in an illustrative embodiment. FIG. 8B is a sideview of a cured laminate 810 in an illustrative embodiment. As shown inFIG. 8A, the rigid filament fasteners 850 may be inserted stiff atinstallation. The rigid filament fasteners 850 may include a compositematerial that is pierced through 801 or cut internally 802 to form amonolithic composite structure. Alternatively, the rigid filamentfasteners 850 may include a metal material 803 that embeds in theuncured laminate 800. The rigid filament fasteners 850 may be installedfrom a roll or packaged in a cartridge or band and inserted with a nailgun device. As shown in FIG. 8B, after co-curing with the laminate, therigid filament fasteners 850 conform to the forming surfaces of thecured laminate 810.

FIG. 9 illustrates a composite part 900 enhanced with filament fasteners950 in another illustrative embodiment. In addition to being consumedwithin a part to prevent delamination, filament fasteners 950 may beused to integrate multiple parts together to prevent delaminationbetween the parts. In this example, the filament fasteners 950 integratea skin panel 910 and a stringer 920. Accordingly, filament fasteners 950may be installed through a layup or stack of multiple parts to be curedtogether. The filament fasteners 950 may thus join to or more parts, orlaminates, together in a co-cure technique to stop disbond where thelaminates are joined. Alternatively or additionally, the filamentfasteners 950 may be used to improve radius strength or interlaminartension. If the filament fasteners 950 are used in a single laminate asdescribed above it prevents delamination due to impact. Another exampleof parts that may be integrated by filament fasteners 950 includesstiffeners and bulkheads.

FIG. 10A is a perspective view a joint fastener 1000 that includes anarray of filament fasteners 1050 in an illustrative embodiment. Thejoint fastener 1000 includes a disc body 1020 and an array 1030 ofmembers extending from a bottom surface of the disc body 1020, whereineach member comprises a filament fastener 1050. The array of members areconfigured to cure within a composite stack (e.g., wet/dry preform) tobind the layers of the composite material as described in further detailbelow. Alternatively or additionally, the joint fastener 1000 may beused with an adhesive to fasten parts post-cure.

FIG. 10B is a perspective view of a series of steps of installing thejoint fastener 1000 with a laminate 1060 in an illustrative embodiment.FIG. 10C is a side view of the series of steps of installing the jointfastener 1000 with the laminate 1060 in an illustrative embodiment. FIG.10D is a partial bottom view of the joint fastener in an illustrativeembodiment. In step 1001, the laminate 1060 is drilled with crookedholes. In step 1002, the joint fastener 1000 is provided. In step 1003,the filament fasteners 1050 of the joint fastener 1000 are squeezed to astraight position to pilot with the holes. In step 1004, the filamentfasteners 1050 are pressed through the crooked holes of the laminate1060. In step 1005, the disc body 1020 is adhered to the top surface ofthe laminate 1060 with adhesive. Alternatively or additionally, thejoint fastener 1000 is co-cured with the laminate 1060. Alternatively oradditionally, a button 1070 is slid over the filament fasteners 1050 atthe back side of the laminate 1060.

The embodiments of the disclosure may be described in the context of anaircraft manufacturing and service method 1100 as shown in FIG. 11 andan aircraft 1200 as shown in FIG. 12. During pre-production, exemplarymethod 1100 may include specification and design 1104 of aircraft 1200,and material procurement 1106. During production, component andsubassembly manufacturing 1108 and system integration 1110 of aircraft1200 takes place. Thereafter, aircraft 1200 may go through certificationand delivery 1112 in order to be placed in service 1114. While inservice by a customer, aircraft 1200 is scheduled for routinemaintenance and service 1116 (which may also include modification,reconfiguration, refurbishment, and so on).

Each of the processes of method 1100 may be performed or carried out bya system integrator, a third party, and/or an operator (e.g., acustomer). For the purposes of this description, a system integrator mayinclude without limitation any number of aircraft manufacturers andmajor-system subcontractors; a third party may include withoutlimitation any number of venders, subcontractors, and suppliers; and anoperator may be an airline, leasing company, military entity, serviceorganization, and so on.

As shown in FIG. 12, aircraft 1200 produced by exemplary method 1100 mayinclude an airframe 1202 with a plurality of systems 1204 and aninterior 1206. Examples of high-level systems 1204 include one or moreof a propulsion system 1208, an electrical system 1210, a hydraulicsystem 1212, and an environmental system 1214. Any number of othersystems may be included. Although an aerospace example is shown, theprinciples described in this specification may be applied to otherindustries, such as the automotive industry.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of the production and service method 1100. Forexample, components or subassemblies corresponding to production process1108 may be fabricated or manufactured in a manner similar to componentsor subassemblies produced while aircraft 1200 is in service. Also, oneor more apparatus embodiments, method embodiments, or a combinationthereof may be utilized during the production stages 1108 and 1110, forexample, by substantially expediting assembly of or reducing the cost ofaircraft 1200. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while aircraft1200 is in service, for example and without limitation, to maintenanceand service 1116.

Any of the various elements shown in the figures or described herein maybe implemented as hardware, software, firmware, or some combination ofthese. For example, an element may be implemented as dedicated hardware.Dedicated hardware elements may be referred to as “processors”,“controllers”, or some similar terminology. When provided by aprocessor, the functions may be provided by a single dedicatedprocessor, by a single shared processor, or by a plurality of individualprocessors, some of which may be shared. Moreover, explicit use of theterm “processor” or “controller” should not be construed to referexclusively to hardware capable of executing software, and mayimplicitly include, without limitation, digital signal processor (DSP)hardware, a network processor, application specific integrated circuit(ASIC) or other circuitry, field programmable gate array (FPGA), readonly memory (ROM) for storing software, random access memory (RAM),non-volatile storage, logic, or some other physical hardware componentor module.

Also, an element may be implemented as instructions executable by aprocessor or a computer to perform the functions of the element. Someexamples of instructions are software, program code, and firmware. Theinstructions are operational when executed by the processor to directthe processor to perform the functions of the element. The instructionsmay be stored on storage devices that are readable by the processor.Some examples of the storage devices are digital or solid-statememories, magnetic storage media such as a magnetic disks and magnetictapes, hard drives, or optically readable digital data storage media.

Although specific embodiments were described herein, the scope is notlimited to those specific embodiments. Rather, the scope is defined bythe following claims and any equivalents thereof.

What is claimed is:
 1. A composite laminate comprising: layers ofreinforcement fibers forming a stack of composite material to be curedwith a first resin; and a filament fastener including bundled fiberswith one or more texture elements around the bundled fibers, and asecond resin chemically compatible with the first resin that saturatesthe filament fastener, wherein the filament fastener is configured toinsert into the stack through a plurality of the layers of reinforcementfibers, and to cure within the stack to bind the layers of the stackwith the one or more texture elements of the filament fastener viabonding of the first resin and the second resin to form the compositelaminate with delamination resistance.
 2. The composite laminate ofclaim 1 wherein: the one or more texture elements spiral around thebundled fibers in a helical shape.
 3. The composite laminate of claim 1wherein: the filament fastener is configured to integrate within thestack during the cure to form a monolithic composite structure.
 4. Thecomposite laminate of claim 1 wherein: the filament fastener includes atip configured to separate the reinforcement fibers as the filamentfastener is inserted through a plurality of plies of the stack ofcomposite material.
 5. The composite laminate of claim 1 wherein: thefirst resin and the second resin comprise a common resin material. 6.The composite laminate of claim 1 wherein: the stack comprises aprepreg.
 7. The composite laminate of claim 1 wherein: the stackcomprises a preform.
 8. The composite laminate of claim 1 wherein: thefilament fastener comprises a core thread of the bundled fibers with aring texture around the core thread.
 9. The composite laminate of claim8 wherein: the ring texture is oriented on the core thread via a resin.10. The composite laminate of claim 8 wherein: the core thread forms acentral spike.
 11. The composite laminate of claim 1 wherein: thefilament fastener forms a screw, and a pitch of the filament fastenercorresponds with a thickness of each layer of the composite laminate.12. An apparatus comprising: a filament fastener comprising: a corethread comprising bundled fibers; a texture thread wrapped around thecore thread in a spiral; and a resin that saturates the filamentfastener and orients the texture thread with respect to the core threadto form the filament fastener in a helical shape, the filament fastenerconfigured to insert into a composite laminate through one or morelayers of reinforcement fibers laid up as a stack of composite material,and to cure within the stack via the resin to bind the layers with thetexture thread of the filament fastener.
 13. The apparatus of claim 12further comprising: a joint fastener: a disc body; and an array ofmembers extending from a bottom surface of the disc body, each of themembers comprising the filament fastener, wherein the array of memberscure within the stack to bind the layers of the composite material. 14.The apparatus of claim 12 wherein: a surface area of the texture threadpromotes bonding of the filament fastener to the stack of compositematerial during the cure to prevent delamination of the compositelaminate.
 15. The apparatus of claim 12 wherein: the filament fastenerincludes a diameter configured to separate fibers of the compositelaminate as the filament fastener is inserted into the compositelaminate.
 16. The apparatus of claim 12 wherein: the filament fasteneris configured to integrate multiple composite laminates.
 17. Theapparatus of claim 12 wherein: the filament fastener is configured tointegrate within the stack during the cure to form a monolithiccomposite structure.
 18. The apparatus of claim 12 wherein: the filamentfastener is spooled as a continuous thread that is inserted into thecomposite laminate.
 19. The apparatus of claim 12 wherein: the filamentfastener is stitched into the composite laminate.
 20. The apparatus ofclaim 12 wherein: the filament fastener forms a screw, and a pitch ofthe filament fastener corresponds with a thickness of each layer of thecomposite laminate.